Viruses. 2016 Aug; 8(8): 210.

Abstract
Measles virus is a highly contagious negative strand RNA virus that is transmitted via the respiratory route and causes systemic disease in previously unexposed humans and non-human primates. Measles is characterised by fever and skin rash and usually associated with cough, coryza and conjunctivitis. A hallmark of measles is the transient immune suppression, leading to increased susceptibility to opportunistic infections. At the same time, the disease is paradoxically associated with induction of a robust virus-specific immune response, resulting in lifelong immunity to measles. Identification of CD150 and nectin-4 as cellular receptors for measles virus has led to new perspectives on tropism and pathogenesis. In vivo studies in non-human primates have shown that the virus initially infects CD150+ lymphocytes and dendritic cells, both in circulation and in lymphoid tissues, followed by virus transmission to nectin-4 expressing epithelial cells. The abilities of the virus to cause systemic infection, to transmit to numerous new hosts via droplets or aerosols and to suppress the host immune response for several months or even years after infection make measles a remarkable disease. This review briefly highlights current topics in studies of measles virus host invasion and pathogenesis.

Keywords: measles virus, immune suppression, pathogenesis, tropism, transmission

Proc R Soc Med. 1974 Nov;67(11):1120-2.

Introduction
The roots of immunology are to be found in the study of immunity to infectious disease and particularly to viruses. Long before an antibody – not to mention complement or a cytotoxic T cell – had ever been heard of, it was recognized that prior exposure to smallpox virus, or subsequently to vaccinia virus, gave immunity to
subsequent smallpox infection. From these beginnings grew the study of prophylactic immunization against virus infection which probably remains medicine’s major single achievement. Dr Beale (p 1116) has already discussed the
vaccines that have recently been developed for the prophylaxis of measles. There can be no doubt, therefore, that the allergic response to viruses is a ‘good thing’. Nevertheless, it must be recognized that the very allergic responses that prevent virus infection can also play a major part in the pathogenesis of virus disease. This is by no means a new idea. In 1902 von Behring suggested that many of the manifestations of acute infectious disease – the incubation period, the fever, the exanthem – could be explained on an allergic basis. In this, as in so many other things, von Behring showed great insight, as much subsequent work has demonstrated (see Coombs
etal. 1974).
This involvement of immunological processes in the manifestations of the acute virus infection makes a convenient first heading under which to discuss the immunopathology of measles. The involvement of immunological processes in the complications of measles form a second heading and the involvement of immunological responses to measles virus in diseases that are not obviously caused by measles infection at all provides the third.